Process of making hollow rubber articles.



F. J. GLEASON. A PROCESS 0F MAKING HOLLOW RUBBER ARTICLES.

APPLICATION FILED DEG.7.1907 Patented Jaln 19,

2 SHEETS-SHEET 1.

F. JFGLEASON. PROCESS 0F MAKING HOLLOW RUBBER ARTICLES.

i APPLICATION FILED DEG.7,1907. 91 0,370.

2 SHEETS-SHEET 2.

Patented Jan. 19, 1909.

UNITED STATES PATENT oFFroE.

FREDERICK I. GLEASON, OF WALPOLE, MASSACHUSETTS, ASSIGNOR OF ONE-HALF TO ALVI T. BALDWIN, -OF BUFFALO, NEW YORK.

l PROCESS OF MAKING HOLLOW RUBBER ARTICLES.

Specification of Letters Patent.

` .Patented Jan. 19, i909.

Application filed December 7, 1907. Serial No. 405,507.

vof which the following is a specification.

This invention has relation to the manufacture of hollow goods of vulcanized rubber,

such as vehicle tires, hollow cushions for billiard tables, hose pipe, balls, and the like, and has for its object an improved methodof making such articles so that they shall be seamless when finished.

,I have found that rubber can be cured oil vulcanized Vwhile in Contact with fusible materials which melt' at the same or at a lower temperature than the cui'ing or vulcanizing tem erature ofV rubber, without injuring the ru ber, and hence inthe manufacture of hollow rubber articles, I employ a fusible core or mandrel, which when cold, serves as a form about which the articles may be sha ed, and which becomes molten at a.

desire templerature so that it may easily be withdrawn om the interior of the article, leaving the latter without a seam or joint. I preferably employ for theformation of the mandrel, a material or compound which gives 0E no gases or vapors when melting, and which fuses without ebullition. Metals are prefrablefor this pur ose, and I have found that certain alloys of ismuth, tin and lead may beused to great advantage, as they melt at any desired tem erature, according to the proportions of tllie ingredients, say from 200 to 280 Fahrenheit.

In accordance with m invention, I form a core' or mandrel of suita le material, wrap or placearound it the rubber or rubber compound to be vulcanized into' the desired article and subject it in this` condition to the 'vulcanizing heat and pressure .in any suitable vulcanizing apparatus. The article .is naturally. placed-mia mold which is heated, the heat reaching the mandrel by conduction, and effecting the -vulcaniz'ation ofthe rubber article. When the temperature' is high enough, the core or mandrel becomes molten, and after the vulcanization is completed, the

molten core or mandrel is withdrawn from the article, after .the latter has been removed from the molds, by any suitable means.

In manufacturing a vehicle tir, I provide it with a valve tube which is vulcanized in place and through which the molten man drel may be withdrawn practically in liquid form.' In manufacturing other articles, they are punctured at 4a convenient place ,and the material, forming the mandrel, is

Withdrawn or forced out.

On the accompanying drawings, I have illustrated the steps in manufacturing a bicycle tire in accordance with my invention.

Figure 1 represents in section a mandrel formed of suitable material. Fig. 2 represents how the layers of rubber, canvas and the like, may be laid or wrapped about the mandrel. the tire prior to removing the material of which the mandrel is com osed.V Fig. 4 illustrates how the materia forming the mandrel, may be withdrawn from the interior of the tire by a Siphon. Fi 5 represents the tire placed in the mo ds ready for vulcanizing. Fig. 6 represents a section through the same.

tion of a finished tire. Fig. 8 represents a rubber ball with a fusible mandrel therein,

the ball and mandrel being shown in section. Fig. 9 represents the linished ball.

I desire to have it understood at the outset that the invention is not limited to the r.manufacture of any particular article, since it may be employed for manufacturing all 'sorts of hollow rubber articles, that the hraseology which I employ in the spec cation and claims is for the purpose of description and not of limitation, and that the rocess or method which I shall describe in etail may be carried out in other ways than those illustratedand described without departing from the s irit and scope of the invention.

Re eiring to the drawings, a, represents an annular mandrel which is circular in crosswhich will melt at a relatively low tem erature Without givin off gases and wit out ebullition.' Prefera ly, I form this mandrel Fig. 3 represents a section through Fig. 7 represents a por- Afterr the mandrel has i or core of an alloy of tin, bismuth and lead in the pro ortion of five (5) parts by weight of bismut three (3) parts b weight of tin and two (2) parts by weight o lead. An alloy of this character will melt at approximately from 199 to 201 Fahrenheit. About the mandrel, I place layers of rubber and canvas or other material which may be utilized to strenfgthen the tire or to render it puncture roo P On account of the relatively low melting point of the mandrel, I :find 1t desirable in some cases,-to employ, as the first wrapping. or layer, a strip of rubber which has been previously cured orvulcanized. The other layers of rubber or rubber com ounds are preferably green or uncured. n Fig. 2, the first layer, Whichis of vulcanized rubber, is indicated at b. The second layer, indicated conventionally at c, is formed of canvas and about these are placed as many more layers indicated conventionally at d of rubber or rubber and canvas as may be found desirable.

een completely inclosed, as illustrated in Fig. 3, there being inserted, as at e, a steel tube which will serve as a valve tube, the mandrel with its inclosin wrpping is laced in molds indicated at f in ig 5 t will be understood, of course, that the molds are properly formed to give the desired exterior shape to the tire.' The molds are vthen placed in any suitable vulcanizing press where they are subjected to the desired heat. Rubber is vulcanized at a proximately 280 Fahrenheit, and as t e eat works inward, as it were, into the tire,

Y the vulcanization takes dplace from the eX- terior inward. The mol are of course sub- -ected to great pressure as ordinarily. The

eat to which the molds are lsubjected is suficient to melt the material formin the mandrel a, so that, when the vulcanize tire is removed from the molds, the material forming the mandrel is in a molten conditionso that it may be withdrawn from the interior of the tire by any suitable means.

I have shown in Fig. 4 how a Siphon may be utilized to withdraw the metal which .does not run out freelywhen the tire is arranged upright. The sphon is indicatedby dotted lines at and ts loosely within the steel valve tu e e.' The same .material maybe then run into molds so as to be shaped again into mandrel form. A, complete tire, of which a section is shown in Fig. 7, is formed in this way without joint or seam, and. is

practically impervious to air so that there is- So far as I am aware, I am the first to have em loyed in the manufacture of hollow artic es of vulcanized rubber, a fusible mandrel which is solid before the article is subjected to the curing or vulcanizin process and which becomes sufliciently fluid, when heated, to be withdrawn. I em loy the alloy, previously referred to, in the proportions given, for-fthe reason that it melts at a lower temperaturethan that of boiling water', and consequently, in the event .that any of the metal sticks to the interior wall of the article, I have merely to fill the article with boilin water to effect the meltin of the metal and its removal from the wa l. Of course, in lieu thereof, I may employ any other material which melts at a point below a tem eramade.

1. The herein described method of making seamless, hollow articles of vulcanized rubber, .which consists in forming the article of vulcanizable material about an initiallysolid core fusible below a temperature destructive to thearticle, subjecting the article to vulcanization, and withdrawing the core in molten condition.

2.. The herein described method of making seamless, hollow articles of vulcanized rubber, which consists in forming the article of vulcanizable material about an initiall -solid core consisting of a metallic alloy fusi le below a temperature destructive to the article, subjecting the article to vulcanization, and withdrawing the core in molten condition.

3. The herein described method of making seamless vulcanized rubber tubes, which consists in forming a tubular structure of vulcanizable material. about an initiallysolid mandrel or core of material fusible below a temperature destructive to the article, vulcanizing the tube thus formed, and withdrawing the mandrel in molten condition.

` 4. The herein described method of making Vseamless vulcanized .rubber tubes, which consists in forming a tubular structure of vulcanizable material about an initiallysolid mandrel or core of a metallic alloy fusible below a temperature destructive to the article, vulcanizing the tube thus formed, and withdrawing the mandrel in molten condition.

5. The herein described method of making seamless vulcanized rubber tires, which consists in for an endless tubular structure of vulcanizab e material about an endless initially-solid mandrel or core of fusible ture which is destructive to the article eing material, Vulcanizing the3 tire thus formed, formed, and .withdrawing the mandrel in 1o and withdrawing the mandrel in molten conmolten condition. dition. In testimony whereof I have aflixed my 6. The herein described method of making signature, in presence of two witnesses. seamless vulc'anized rubber tires, which consists in forming en endless tubular struoi FREDERICK J GLEASON ture of vulcanizable material about an end- Witnesses: less initially-solid mandrel or core of fusible MARoUs'BILLAY,

metallic alloy, vuloanizihg the tire thus ARTHUR H. BROWN. 

